Future mobile communications are expected to demand a higher data rate and a greater capacity as mobile devices remarkably change and sharply increase in number. Hence, millimeter wave (mmWave) is used between a Base Station (BS) and a Mobile Station (MS), and beamforming for efficient signal transmission and reception in the mmWave are under consideration.
The BS and the MS selects an optimal beam using beam scanning. However, since the BS supports a plurality of transmit beam directions and a plurality of receive beam directions of the MS, it takes a great time and great complexity to determine an optimal transmit beam and an optimal receive beam. Further, when the MS travels, the optimal transmit/receive beams change frequently. When the optimal transmit/receive beams change, control information required to re-determine the optimal transmit/receive beams cause considerable overhead. As discussed above, diverse variables are considered in order to maintain the optimal transmit/receive beams in the communication system using the beamforming. Thus, what is needed is a method for determining the optimal beam with low complexity for less time.